Help - Search - Members - Calendar
Full Version: Juno perijove 5
Unmanned Spaceflight.com > Outer Solar System > Jupiter > Juno
Pages: 1, 2
Bjorn Jonsson
Juno's perijove 5 is coming up less than two weeks from now - it's on March 27, 2017.

The target selection voting has started and is open until almost four days from now: https://www.missionjuno.swri.edu/junocam/voting?current

A large part of the data volume will be reserved for polar time lapse sequences though.

John Rogers has written a helpful summary of the upcoming perijove 5: https://www.britastro.org/node/9377
PhilipTerryGraham
An insignia for perijove 5 that I made for the subreddit. smile.gif

Click to view attachment
JRehling
Nice, Philip! (The board should have "Like" button…)
belleraphon1
Very cool Philip!

My desktop for March 27th

You plan to make one for each perijove?

Craig
PhilipTerryGraham
Ehyup! I've got a few ideas for graphics each time the spacecraft comes 'round. cool.gif
PhilipTerryGraham
The word from NASA: all instruments will be on, and the spacecraft will be making a closest approach of around 4,400 kilometers, with a top speed of 57.8 kilometers per second, relative to Jupiter.
PhilipTerryGraham
Here's what Juno's signal looked like at closest approach on Perijove 5, capped from DSN Now at 09:30 UTC (08:57 UTC + 37 minutes, the current light travel distance from Earth to Jupiter). This has occurred only 7 minutes ago, as of me posting this.

Click to view attachment
PhilipTerryGraham
Madrid downlinking data from the spacecraft at the moment, at a rate of 40 kilobits per second according to DSN Now. Fun fact - this is 325 times slower than the average download speed of my ADSL2 modem. I feel like I've been taking my Australian copper wire internet for granted. tongue.gif
Bjorn Jonsson
On the other hand this is almost 1000 times faster than the typical Galileo downlink speed from Jupiter was.
PhilipTerryGraham
Imagine how different the Galileo mission would've been if that High-gain antenna had worked. unsure.gif
Explorer1
Things would be quite different, though I always prefer to look at the bright side of the Jupiter data loss. I bet there would be more missions afterward with antennas that deployed mechanically long after launch, and some other mission would have had the issue. We know better now.
Bjorn Jonsson
That was fast - the PJ5 images are now available at the Juno website.
PhilipTerryGraham
The image of Trevmation's Dark Spot was reportedly taken at a distance of only 3,421.8 km, according to its metadata. Can this be true? Because if so, that's a thousand kilometers less than expected, and most certainly the closest approach of the mission so far. ohmy.gif
Gerald
Usually the metadata are pretty accurate. However, I'm in an early phase of processing, so can't yet verify by the images.

... Here an enhanced draft of PJ05, #109, rendered from the raw, yet without proper calibration nor trajectory or shape model, therefore the color channel poorly aligned. However, it's very facinating already, including dark boundaries along clouds, which look like shadows.
Click to view attachment
mcaplinger
QUOTE (PhilipTerryGraham @ Mar 28 2017, 03:43 PM) *
The image of Trevmation's Dark Spot was reportedly taken at a distance of only 3,421.8 km, according to its metadata. Can this be true? Because if so, that's a thousand kilometers less than expected...

Expected by who?

Obviously the metadata was computed with a predicted spacecraft position and that may change a little once we have the reconstruction, but I'm fairy confident that the calculation is right. Keep in mind that because of Jupiter's oblateness, the geometry to figure out the altitude is a little more complex than simply taking the distance to the center of Jupiter and subtracting the radius of Jupiter, which is what a simple calculation might do.

Here's the code that computes the metadata if you're interested (in Python, using NAIF/pyspice):
CODE

te = spkezr("juno", t, "iau_"+target, "LT+S", target)[0][0:3]
radii = bodvrd(target, "RADII", 3)[1]
lon, lat, alt = recpgr(target, te, radii[0], (radii[0]-radii[2])/radii[0])
Gerald
Polar projection of PJ-05 image #111, and detail, enhanced in different ways:
Click to view attachment
(NASA / JPL / SwRI / MSSS / Gerald Eichstädt)

Thanks to the Juno-Ops team for your outstanding work! Despite the tight memory constraints of PJ05, we've got a sequence of images of high quality, as far as I can already say about the images I've preliminarily processed thus far.
PhilipTerryGraham
Looks like Jupiter is happy to see Juno again wink.gif

Click to view attachment
Roman Tkachenko
Jupiter, Io and Europa.
mcaplinger
Lightly-processed quicklook version of image pj5-110. I'm sure others will do a better job.

Click to view attachment
Roman Tkachenko
#110
Decepticon
Roman that is beautiful!
Gerald
Is it possible to discern any rotation in these large storms within the five and a half minutes between images #109 and #110?
My best candidate is the large white (anticyclonic) oval A6:
Click to view attachment
(crop of cylindrical planetocentric projection with 60 pixels / deg, de-Lambertianed, and further enhanced, north to the right)
Decepticon
Can Juno image lightning on the dark side?
Gerald
Yes, but there are also energetic particle events and camera artifacts. So, we need to look twice, before making conclusions.
Gerald
Spacecraft changing spin axis (and observation mode) during PJ05 approach:
Click to view attachment
Colors approximately radiometric, then square-root encoded. South is up. Note the Great Red Spot, and a moon shadow.

For this sequence, I've calibrated my simplfied geometrical camera model for each image separately during an overnight calibration run.
With this kind of sequences covering spacecraft attitude changes, I'm hoping and expecting to be able to further narrow down the actual geometrical camera properties, among other approaches.
Gerald
For completeness, here the statistics resulting from the calibration run:
Click to view attachment
There are peaks and discontinuities near the change of the s/c spin axis.

But at least the camera's optical axis shouldn't change during these maneuvers, with the x-position near 812. The inconsistencies indicate residual flaws in the model, and help to uncover them.
Roman Tkachenko
#109
scalbers
That has some super detail in it, including what look like convective cloud elements. Do we know what the pixel resolution is? Considering the context, these convective clouds on the right are in a zone, with overall low altitude clouds, so that we see more into a water rich level. The redder clouds on the left are in a higher belt. It seems the bluer nature of the zone would be consistent with looking through some overlying clear air with attendant Rayleigh scattering.
mcaplinger
QUOTE (scalbers @ Apr 2 2017, 11:33 AM) *
Do we know what the pixel resolution is?

Altitude from the metadata is 12744 km, so resolution is 673e-6*12744 = 8.6 km/pix at nadir.
scalbers
Thanks - we can see the sizes of the convective clouds are similar to thunderstorms on Earth.
Bjorn Jonsson
QUOTE (Gerald @ Apr 2 2017, 08:51 AM) *
For completeness, here the statistics resulting from the calibration run:

Have you checked how accurate the interframe delay in the metadata is? For the PJ5 images it is 0.371 but I'm starting to suspect that I might get slightly better results by adjusting it slightly. I haven't tried it yet though but I'm pretty sure any adjustment (if needed) is less than 0.001.

QUOTE (Gerald @ Mar 31 2017, 11:45 PM) *
Is it possible to discern any rotation in these large storms within the five and a half minutes between images #109 and #110?
My best candidate is the large white (anticyclonic) oval A6:

Quick back of the envelope calculations seem to suggest this *might* be possible. The elapsed time between the images is ~330 seconds. Assuming a wind speed of ~60 m/s near the A6 spot's periphery (a very crude but probably not bad assumption made by scaling down the speed in the bigger white oval BC in the Voyager era by a factor of ~2 since A6 is smaller) results in a ~20 km movement. This corresponds to roughly 2-3 pixels in the higher-res image which is noticeable if the images are well aligned.

QUOTE (scalbers @ Apr 2 2017, 07:33 PM) *
That has some super detail in it, including what look like convective cloud elements. Do we know what the pixel resolution is? Considering the context, these convective clouds on the right are in a zone, with overall low altitude clouds, so that we see more into a water rich level. The redder clouds on the left are in a higher belt. It seems the bluer nature of the zone would be consistent with looking through some overlying clear air with attendant Rayleigh scattering.

Hmmm... but I have always been under the impression that the whitish zones are higher in the atmosphere than the darker and more reddish/brownish belts and that they are probably ammonia cirrus (the water clouds are much lower in the atmosphere and look darker and more fuzzy). But the possible convective clouds in Roman's image are very interesting. An interesting fact is that these small, whitish clouds are very common and not just in Roman's image. They occur both as isolated features, e.g. at ~(435,740) and in 'clusters', e.g. at ~(980,105) in Roman's image above. And there's a lot of them in the whitish zone. Some of them look like cumulus to me. These clouds seem to occur at various locations although some areas are more likely to have them than others.

There are also small/narrow 'elongated', whitish clouds at various locations, typically above darker clouds. I suspect their altitude is similar to the convective/cumulus clouds. Here is an example, an enhanced crop from an image (PJ5 image 110) I'm working on:
Click to view attachment
mcaplinger
QUOTE (Bjorn Jonsson @ Apr 2 2017, 04:10 PM) *
Have you checked how accurate the interframe delay in the metadata is? For the PJ5 images it is 0.371...

The metadata value is 1 millisecond too small (there was an off-by-one misunderstanding about how the hardware interpreted the commanded interframe value.) Otherwise it's under the control of a fairly stable crystal oscillator but there could be some drift on order of 10-20 PPM over temperature.

The spacecraft spin rate is usually not precisely 2.000 RPM so that's probably a bigger unknown.
scalbers
QUOTE (Bjorn Jonsson @ Apr 3 2017, 12:10 AM) *
Hmmm... but I have always been under the impression that the whitish zones are higher in the atmosphere than the darker and more reddish/brownish belts and that they are probably ammonia cirrus (the water clouds are much lower in the atmosphere and look darker and more fuzzy). But the possible convective clouds in Roman's image are very interesting. An interesting fact is that these small, whitish clouds are very common and not just in Roman's image. They occur both as isolated features, e.g. at ~(435,740) and in 'clusters', e.g. at ~(980,105) in Roman's image above. And there's a lot of them in the whitish zone. Some of them look like cumulus to me. These clouds seem to occur at various locations although some areas are more likely to have them than others.
Click to view attachment

Thanks Bjorn for the correction/clarification. I was somewhat influenced by the appearance of the image where it seemed like some of the belt clouds were running on top of the zone clouds at the border - perhaps an illusion. I will suggest that the zones would have a mix of elevation as I believe IR hot-spots (bluish in visible) tend to occur in the zones and we may be seeing some of these on a small scale in this closeup. These hot-spots are areas with very few (or very low) clouds. It would be interesting to look at closeup IR data or something like that to tell the relative altitude of the convective cloud bottoms and tops relative to the more stratiform white (ammonia) clouds. Maybe stereo images can help on this as well.

Within the belts, are the white spots higher or lower than the surrounding reddish clouds?
Bjorn Jonsson
QUOTE (scalbers @ Apr 3 2017, 12:45 AM) *
Maybe stereo images can help on this as well.

I think it might be possible to use images 109 and 110 as a stereo pair. I haven't tried it yet but probably will.
scalbers
This is a good learning experience for me. If we look at this hi-res IR/visible pair we can see most of the hot spots are in the brown belts as you suggest. However some bluish areas continue into the zones with "suppressed" IR warmings. This suggests to me the bluish areas in the zones are areas fairly cold in IR with thin high ammonia haze, while also allowing us a partially transparent view with scattered visible light into much lower altitudes.

http://www.dailymail.co.uk/sciencetech/art...approaches.html (scroll down page to see image pair and look just right of center in the images)

Areas that are dark within the belts look to be the hottest of all, perhaps no clouds are present at all in these locations.

Will be interesting if we can see some simultaneous images of the VLT IR data and Juno. The link is showing images from the ESO VLT and ground-based visible light images as a dry run for the Juno observing campaign.

A similar situation occurs with satellite images of Earth with thin cirrus clouds. The IR signature looks cold while in the visible it can be relatively dark (blue in color) with the ground still evident.
jccwrt
QUOTE (Bjorn Jonsson @ Apr 2 2017, 06:10 PM) *
Hmmm... but I have always been under the impression that the whitish zones are higher in the atmosphere than the darker and more reddish/brownish belts and that they are probably ammonia cirrus (the water clouds are much lower in the atmosphere and look darker and more fuzzy). But the possible convective clouds in Roman's image are very interesting. An interesting fact is that these small, whitish clouds are very common and not just in Roman's image. They occur both as isolated features, e.g. at ~(435,740) and in 'clusters', e.g. at ~(980,105) in Roman's image above. And there's a lot of them in the whitish zone. Some of them look like cumulus to me. These clouds seem to occur at various locations although some areas are more likely to have them than others.


It's possible that the white spots are a form of pileus in the ammonia cirrus deck or perhaps even overshooting tops of water vapor cumulus. Given some of the Voyager images you found in a similar region last year, I'm inclined to say it's the latter, but I don't know enough about Jovian meteorology to say if a water vapor-driven updraft is capable of rising that high through the cloud deck without collapsing.

QUOTE (scalbers @ Apr 2 2017, 07:00 PM) *
This is a good learning experience for me. If we look at this hi-res IR/visible pair we can see most of the hot spots are in the brown belts as you suggest. However some bluish areas continue into the zones with "suppressed" IR warmings. This suggests to me the bluish areas in the zones are areas fairly cold in IR with thin high ammonia haze, while also allowing us a partially transparent view with visible light into much lower altitudes.


The equatorward side of the equatorial belts is marked by a vertical jet stream oscillation. You get an IR hotspots where the jet stream is descending and warming the air through adiabatic heating. That clears out the upper cloud decks to give us an unobstructed view deep into Jupiter (probably down to the water cloud layer), which correspond with the dark blue areas in the VIS along the edge of the belt. The ascending portion oscillation generates a long-lived convective updraft that encourages the formation of ammonia cirrus muddied with some of the ammonium sulfate cloud layer that's been carried upwards. Most of that cirrus drifts equatorwards, but some of it gets entrained within the belt circulation patterns and is forming an IR-blocking layer that shows up against the bright IR radiation emitted from the belts. The belts are also a region of generally descending air, so you might also be getting variable IR bright spots where the ammonium sulfate clouds are being eroded more deeply by adiabatic heating.
scalbers
We can see these variable hot-spots in the belts as I'm here reproducing one of the images from the link in post #35. The IR blocking areas in the belts appear to be where white clouds are mixing with the red ones. However the white clouds in the belts appear different in nature/structure than the white clouds in the zones (in #109), so it's unclear to me whether entrainment from the zones is really going on.

Click to view attachment

The convective clouds in #109 are mostly in a zone, so I wonder if the visible cumuliform cloud is all an overshooting top, or if we can see (through the cirrus) deeper to the source region of the water vapor. It also seems like the rising motion in the zones would be dynamically forced on the large scale with the convection happening more on the small scales. I would continue to entertain the notion that in the zones we're seeing a combination of thin white high ammonia haze, with more structured denser white clouds at a lower altitude. This possibly explains why we see structure in the visible and not so much in the IR. The convection could be happening between these two levels. Some of the darker areas in the zones (and belts) would be where we are seeing even deeper.

This link is actually suggesting that the zones have large scale descent. Though it's interesting that they say most convective elements are in the belts. Maybe that's true of some larger storms that could be seen in the Cassini flyby in 2000, or the embedded convective elements in the whiter clouds within the belts as in Bjorn's image in post #31. Perhaps looking at Juno's images now is giving some fresh perspectives on all this. Possibly larger convective storms tend to be in the belts and smaller ones in the zones.

On another note I can see rotation in Gerald's oval A6.
Bjorn Jonsson
Here's everything from image 110 ("String of Pearls" plus more) processed from the raw framelets. First an approximately true color/contrast version (small scale features have been sharpened a bit, partially simply to compensate for all of the resampling steps during processing):

Click to view attachmentClick to view attachmentClick to view attachment

And then a version of these images where the effects of global illumination have been removed and the contrast, color saturation and sharpness exaggerated:

Click to view attachmentClick to view attachmentClick to view attachment

Most/all of the features here are also visible in image 109 posted earlier by Roman but the resolution of that image is higher. As mentioned earlier it might be possible to use images 109 and 110 as a stereo pair.

Juno's altitude was ~20,000 km when the image 110 framelets were obtained. The processing is more or less identical to what I did when I processed a PJ-4 image some time ago.

These images reveal lots of interesting features, some of which are relevant within the context of the interesting Jovian weather/clouds discussion above. "String of pearls" oval A6 is visible. I find the circular storm SSW of oval A6 particularly interesting. Cloud shadows are visible within it and elongated, elevated clouds within the storm apparently form a spiral.
Gerald
Outstanding work, Björn!
I didn't yet include full illumination adjustment into my renditions, but am curious how those results will eventually compare to yours. One to three CPU cores are running almost around the clock. So, it will take another few days, before I've completed all "straightforward" products, and find time to dig a little deeper into the data.

I've tried the 109 / 110 pair as stereo, and am not yet quite sure, whether a 3D effect is perceptible. There is also some risk to confuse cloud motion with parallax.

Here some of my "straightforward" products:
PJ05 Approach Movie (and cropped close-ups), level 1, decompanded stills. All images rendered with the same set of parameters (best for distant images), therefore some of them may not be perfectly rgb aligned.
stevesliva
Some quite nice crescent/quarter shots in your stills, Gerald!
scalbers
QUOTE (Gerald @ Apr 4 2017, 12:00 PM) *
I've tried the 109 / 110 pair as stereo, and am not yet quite sure, whether a 3D effect is perceptible. There is also some risk to confuse cloud motion with parallax.

The blinking animation Gerald posted earlier was useful to look at in the context of seeing things in 3D (as a complement to an anaglyph or side-by-side pair). I think it could show some parallax if it is registered more closely. I suppose the risks would be mainly the cloud motion in a rotating spot, or some type of vertical wind shear in a jet region. Other more uniform movements could be compensated for.
Gerald
Departure sequence, level 1 stills, decompanded, some overlap with approach sequence, but slightly different parameter settings.

Most of PJ05 "straightforward" processing completed. Time to work on enhancements, movies, advanced data reduction software, may be another attempt to create stereo products.
Jerry
Click to view attachment

What is the circular cloud formation in this image? Is it just an artifact of processing, or is it something real?

Thanks.
Bjorn Jonsson
This is definitely a real feature, it appears in more than one of the source images (framelets) used to make the final image.
Jerry
QUOTE (Bjorn Jonsson @ Apr 14 2017, 07:20 AM) *
This is definitely a real feature, it appears in more than one of the source images (framelets) used to make the final image.


I don't know if it's possible in a gas medium, but it almost looks like a complex crater.
nprev
It's not possible. It's a complex low or high-pressure center, more likely the former.
Roman Tkachenko
Jupiter at 6000 km
scalbers
QUOTE (nprev @ Apr 14 2017, 11:59 PM) *
It's not possible. It's a complex low or high-pressure center, more likely the former.

There are also some ring shaped IR features in the image I posted in post #37, though I'm unsure if they are analogous.

Very impressive image Roman - looks like a closer view of some convective systems in the upper right.
JRehling
Wow, Roman. In the upper right, there are patterns that crisscross, apparently because a higher cloud layer is translucent and details at two different levels are visible. Unless that's an illusion, that is a very powerful sort of detail, and I don't recall ever seeing something like that in visible light Jupiter imagery before.
Spock1108
Roman congratulations! A crazy image! What is the resolution of this image? Is Beats images of Voyager and Galileo? I have never seen cloudy structures so clear on Jupiter!
This is a "lo-fi" version of our main content. To view the full version with more information, formatting and images, please click here.
Invision Power Board © 2001-2017 Invision Power Services, Inc.